Step‐and‐shoot data acquisition and reconstruction for cardiac x‐ray computed tomography

Abstract

Coronary artery imaging with x-ray computed tomography (CT) is one of the most recent advancements in CT clinical applications. Although existing "state-of-the-art" clinical protocols today utilize helical data acquisition, it suffers from the lack of ability to handle irregular heart rate and relatively high x-ray dose to patients. In this paper, we propose a step-and-shoot data acquisition protocol that significantly overcomes these shortcomings. The key to the proposed protocol is the large volume coverage (40 mm) enabled by the cone beam CT scanner, which allows the coverage of the entire heart in 3 to 4 steps. In addition, we propose a gated complementary reconstruction algorithm that overcomes the longitudinal truncation problem resulting from the cone beam geometry. Computer simulations, phantom experiments, and clinical studies were conducted to validate our approach.

Determinants of vessel contrast in BMI-adapted low dose CT coronary angiography with prospective ECG-triggering

“…First, the amount of contrast material was not BMI-adapted in concordance with a large body of literature [1][2][3][4]6,8], although suggested by a few previous reports [9,10]. However, only the use of a fixed amount of contrast material enabled us to specifically evaluate the influence of BMI on image noise and coronary vessel attenuation.…”

“…Bolus tracking was performed with a region of interest (ROI) placed into the ascending aorta. All CTCA examinations were performed on a LightSpeed VCT XT scanner (GE Healthcare) with prospective ECG-triggering [6] [17]. Axial images for attenuation calculations were reconstructed with a slice thickness of 0.6 mm, using a standard medium softtissue convolution kernel.…”

“…The use of this CTCA protocol allows to reduce radiation dose from about 15mSv in spiral scanning with ECG-modulated tube current down to about 2 mSv [5] by administering radiation dose only at one predefined end-diastolic time point instead of during a whole phase of the cardiac cycle [6].…”

Low-dose CT and cardiac MR for the diagnosis of coronary artery disease: accuracy of single and combined approaches

“…On the other hand, concerns regarding the radiation exposure of patients undergoing CTCA have been raised, which prompted various dose reducing algorithms. One of the most efficient techniques for radiation dose reduction in CTCA is prospective electrocardiography (ECG)-gating, where radiation is only delivered at selected time points of the cardiac cycle [5]. First studies have shown that the lowdose technique for CTCA is accurate for the diagnosis of significant coronary stenoses as compared with CA [6].…”

Multiphase CT Angiography versus Single-Phase CT Angiography: Comparison of Image Quality and Radiation Dose

“…The fully sampled region, the region covered by every view in the scanning, is less than the cylinder, with a height equal to the detector isocenter coverage. 14,15 To overcome this problem, we used extrapolation during the back projection process. The cone beam effect increases farther away from the isocenter and becomes more prominent with a larger FOV.…”